/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * fs/aio/aio_write.c
 *
 *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <stdarg.h>
#include <unistd.h>
#include <fcntl.h>
#include <sched.h>
#include <aio.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include "aio/aio.h"

#ifdef CONFIG_FS_AIO

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Types
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Public Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: file_fcntl
 ****************************************************************************/

#ifdef AIO_HAVE_FILEP
static inline int file_fcntl(FAR struct file *filep, int cmd, ...)
{
	va_list ap;
	int ret;

	va_start(ap, cmd);
	ret = file_vfcntl(filep, cmd, ap);
	va_end(ap);
	return ret;
}
#endif

/****************************************************************************
 * Name: aio_write_worker
 *
 * Description:
 *   This function executes on the worker thread and performs the
 *   asynchronous I/O operation.
 *
 * Input Parameters:
 *   arg - Worker argument.  In this case, a pointer to an instance of
 *     struct aiocb cast to void *.
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void aio_write_worker(FAR void *arg)
{
	FAR struct aio_container_s *aioc = (FAR struct aio_container_s *)arg;
	FAR struct aiocb *aiocbp;
	pid_t pid;
#ifdef CONFIG_PRIORITY_INHERITANCE
	uint8_t prio;
#endif
	ssize_t nwritten = 0;
#ifdef AIO_HAVE_FILEP
	int oflags;
#endif

	/* Get the information from the container, decant the AIO control block,
	 * and free the container before starting any I/O.  That will minimize
	 * the delays by any other threads waiting for a pre-allocated container.
	 */

	DEBUGASSERT(aioc && aioc->aioc_aiocbp);
	pid = aioc->aioc_pid;
#ifdef CONFIG_PRIORITY_INHERITANCE
	prio = aioc->aioc_prio;
#endif
	aiocbp = aioc_decant(aioc);

#ifdef AIO_HAVE_FILEP
	{
		/* Call fcntl(F_GETFL) to get the file open mode. */

		oflags = file_fcntl(aioc->u.aioc_filep, F_GETFL);
		if (oflags < 0) {
			int errcode = get_errno();
			fdbg("ERROR: fcntl failed: %d\n", errcode);
			aiocbp->aio_result = -errcode;
			goto errout;
		}

		/* Perform the write using:
		 *
		 *   u.aioc_filep - File structure pointer
		 *   aio_buf      - Location of buffer
		 *   aio_nbytes   - Length of transfer
		 *   aio_offset   - File offset
		 */

		/* Check if O_APPEND is set in the file open flags */

		if ((oflags & O_APPEND) != 0) {
			/* Append to the current file position */

			nwritten = file_write(aioc->u.aioc_filep, (FAR const void *)aiocbp->aio_buf, aiocbp->aio_nbytes);
		} else {
			nwritten = file_pwrite(aioc->u.aioc_filep, (FAR const void *)aiocbp->aio_buf, aiocbp->aio_nbytes, aiocbp->aio_offset);
		}
	}
#endif

	/* Check the result of the write */

	if (nwritten < 0) {
		int errcode = get_errno();
		fdbg("ERROR: write/pwrite failed: %d\n", errcode);
		DEBUGASSERT(errcode > 0);
		aiocbp->aio_result = -errcode;
	} else {
		aiocbp->aio_result = nwritten;
	}

#ifdef AIO_HAVE_FILEP
errout:
#endif

	/* Signal the client */

	(void)aio_signal(pid, aiocbp);

#ifdef CONFIG_PRIORITY_INHERITANCE
	/* Restore the low priority worker thread default priority */

	lpwork_restorepriority(prio);
#endif
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: aio_write
 *
 * Description:
 *   The aio_write() function writes aiocbp->aio_nbytes to the file
 *   associated with aiocbp->aio_fildes from the buffer pointed to by
 *   aiocbp->aio_buf. The function call will return when the write request
 *   has been initiated or queued to the file or device (even when the data
 *   cannot be delivered immediately).
 *
 *   If prioritized I/O is supported for this file, then the asynchronous
 *   operation will be submitted at a priority equal to a base scheduling
 *   priority minus aiocbp->aio_reqprio. If Thread Execution Scheduling is
 *   not supported, then the base scheduling priority is that of the calling
 *   thread (the latter is implemented at present).
 *
 *   The aiocbp value may be used as an argument to aio_error() and
 *   aio_return() in order to determine the error status and return status,
 *   respectively, of the asynchronous operation while it is proceeding.
 *
 *   The aiocbp argument points to an aiocb structure. If the buffer pointed
 *   to by aiocbp->aio_buf or the control block pointed to by aiocbp becomes
 *   an illegal address prior to asynchronous I/O completion, then the
 *   behavior is undefined.
 *
 *   If O_APPEND is not set for the file descriptor aio_fildes, then the
 *   requested operation will take place at the absolute position in the file
 *   as given by aio_offset, as if lseek() were called immediately prior to the
 *   operation with an offset equal to aio_offset and a whence equal to SEEK_SET.
 *   If O_APPEND is set for the file descriptor, write operations append to the
 *   file in the same order as the calls were made. After a successful call to
 *   enqueue an asynchronous I/O operation, the value of the file offset for the
 *   file is unspecified.
 *
 *   The aiocbp->aio_lio_opcode field will be ignored by aio_write().
 *
 *   Simultaneous asynchronous operations using the same aiocbp produce
 *   undefined results.
 *
 *   For any system action that changes the process memory space while an
 *   synchronous I/O is outstanding to the address range being changed, the
 *   result of that action is undefined.
 *
 * Input Parameters:
 *   aiocbp - A pointer to an instance of struct aiocb
 *
 * Returned Value:
 *
 *   The aio_write() function will return the value zero if the I/O operation
 *   is successfully queued; otherwise, the function will return the value
 *   -1 and set errno to indicate the error.  The aio_write() function will
 *   ail if:
 *
 *   EAGAIN - The requested asynchronous I/O operation was not queued due to
 *     system resource limitations.
 *
 *   Each of the following conditions may be detected synchronously at the
 *   time of the call to aio_write(), or asynchronously. If any of the
 *   conditions below are detected synchronously, the aio_write() function
 *   will return -1 and set errno to the corresponding value. If any of the
 *   conditions below are detected asynchronously, the return status of the
 *   asynchronous operation is set to -1, and the error status of the
 *   asynchronous operation is set to the corresponding value.
 *
 *   EBADF - The aiocbp->aio_fildes argument is not a valid file descriptor
 *     open for writing.
 *   EINVAL - The file offset value implied by aiocbp->aio_offset would be
 *     invalid, aiocbp->aio_reqprio is not a valid value, or
 *     aiocbp->aio_nbytes is an invalid value.
 *
 *   In the case that the aio_write() successfully queues the I/O operation
 *   but the operation is subsequently cancelled or encounters an error, the
 *   return status of the asynchronous operation is one of the values
 *   normally returned by the write() function call. In addition, the error
 *   status of the asynchronous operation is set to one of the error
 *   statuses normally set by the write() function call, or one of the
 *   following values:
 *
 *   EBADF - The aiocbp->aio_fildes argument is not a valid file descriptor
 *     open for writing.
 *   EINVAL - The file offset value implied by aiocbp->aio_offset would be
 *     invalid.
 *   ECANCELED - The requested I/O was cancelled before the I/O completed
 *     due to an explicit aio_cancel() request.
 *
 * The following condition may be detected synchronously or asynchronously:
 *
 *   EFBIG - The file is a regular file, aiobcp->aio_nbytes is greater
 *     than 0, and the starting offset in aiobcp->aio_offset is at or
 *     beyond the offset maximum in the open file description associated
 *     with aiocbp->aio_fildes.
 *
 * POSIX Compliance:
 * - Most errors required in the standard are not detected at this point.
 *   There are no pre-queuing checks for the validity of the operation.
 *
 ****************************************************************************/

int aio_write(FAR struct aiocb *aiocbp)
{
	FAR struct aio_container_s *aioc;
	int ret;

	DEBUGASSERT(aiocbp);

	/* The result -EINPROGRESS means that the transfer has not yet completed */

	aiocbp->aio_result = -EINPROGRESS;
	aiocbp->aio_priv = NULL;

	/* Create a container for the AIO control block.  This may cause us to
	 * block if there are insufficient resources to satisfy the request.
	 */

	aioc = aio_contain(aiocbp);
	if (!aioc) {
		/* The errno has already been set (probably EBADF) */

		aiocbp->aio_result = -get_errno();
		return ERROR;
	}

	/* Defer the work to the worker thread */

	ret = aio_queue(aioc, aio_write_worker);
	if (ret < 0) {
		/* The result and the errno have already been set */

		return ERROR;
	}

	return OK;
}

#endif							/* CONFIG_FS_AIO */
